This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A096489 #12 Jul 04 2025 18:42:17
%S A096489 1,11,13,17,19,23,29,31,37,41,43,47,53,59,61,67,71,73,79,83,89,97
%N A096489 Noncomposite numbers n such that number of decimal digits of n = number of divisors of n.
%C A096489 Only 1 and primes with 2 decimal digits are here, so the sequence is finite: it consists of 1+25-4=22 terms. Part of A008364. Consists of the terms below 100 from A095862.
%t A096489 {u=1, ta=Table[0, {25}]}; Do[s=Apply[Plus, IntegerDigits[n]];s1=Length[IntegerDigits[n]]; If[Equal[s1, DivisorSigma[0, n]], Print[n];ta[[u]]=n;u=u+1], {n, 1, 100}]
%t A096489 Select[Range[100],!CompositeQ[#]&&DivisorSigma[0,#]==IntegerLength[#]&] (* _Harvey P. Dale_, Jan 29 2024 *)
%o A096489 (PARI) print1(1);forprime(p=9,99,print1(", "p)) \\ _Charles R Greathouse IV_, Apr 27 2011
%Y A096489 Cf. A008364, A095862.
%K A096489 base,fini,full,nonn,easy
%O A096489 1,2
%A A096489 _Labos Elemer_, Jun 25 2004